After being switched on, flashlights as a rule operate at full light intensity, although in many individual cases a reduced light intensity would also be sufficient. The service life of the batteries and of the lighting element, i.e. the flashlight bulb or bulbs, is reduced by the constant use at maximum intensity. At the end of their service life they need to be disposed of or, in the case of rechargeable batteries, freshly charged from the power net. The maximum length of operation independently of the power net is limited by this.